Ward Plunet (@StartupYou) header
Ward Plunet (@StartupYou) profile picture

Phd in Neuroscience looking at the intersection between machine learning and neuroscience #machinelearning #AI #neuroscience

Vancouver, Canada
Joined December 2011
Photo by Ward Plunet (@StartupYou)Photo by Ward Plunet (@StartupYou)Photo by Ward Plunet (@StartupYou)Photo by Ward Plunet (@StartupYou)Photo by Ward Plunet (@StartupYou)Photo by Ward Plunet (@StartupYou)Photo by Ward Plunet (@StartupYou)Photo by Ward Plunet (@StartupYou)Photo by Ward Plunet (@StartupYou)Photo by Ward Plunet (@StartupYou)
Ward Plunet retweeted
We cut through the mystery around interpretability in training. A single, mathematically rigorous framework transforms model internals into training feedback and works across domains, problems, and modalities. We call this *mechanistic shaping*, and we’ve used it to mitigate reward hacking, remove shortcuts in chest x-rays, and reduce sycophancy and harmfulness. We believe this is a big step forward for technical alignment. But it carries a known risk: training against a model’s internals can make it harder to monitor. We explore both the technique and this concern below. 🧵
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Ward Plunet retweeted
Neuropixels probes track the activity of hundreds of brain cells simultaneously. nature.com/articles/d41586-0…
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Ward Plunet retweeted
Humans are ~1,000,000x more sample efficient than LLMs, and there are no good explanations. We’ve found that a big part of the answer is that LLMs are *massively* underparameterized by many orders of magnitude. The brain has 100T synapses learning from ~200M tokens of language. Chinchilla prescribes a 1T-parameter model on 20T tokens. That’s 7 OOMs apart in parameters per token. After a lot of painstaking work, we present new data-constrained scaling laws and learning algorithms to scale to (extrapolated) quadrillion-parameter transformers. w/ @akshayvegesna, @EthanBaron78553, @asatheesh6561 Full paper led by @EthanBaron78553, with @ShmuelBerman, @andrewgwils
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Ward Plunet retweeted
Our new paper in Nature Communications reveals an interesting connection between generative diffusion models and Associative Memory. It identifies 3 phases of generated samples: 👉 Memorization: reproducing training examples verbatim. 👉 Spurious states: discovering new patterns between stored memories, while maintaining a well-defined basin of attraction around those samples. 👉 Generalization: generating genuinely novel samples with flat energy landscape around them. The surprising twist? What was traditionally considered a flaw in Associative Memory — spurious states — may actually be the first sign of generative capabilities. It was fun to work on this project with @baophamhq, @gaboraya, Matteo Negri, @mj_zaki, and @LucaAmb, and I am happy to see it published! Paper: nature.com/articles/s41467-0…
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Ward Plunet retweeted
I study AI consciousness and personhood for a living, and people have been telling me to watch this episode for years. I finally watched it for the first time last week, and the writing and acting blew me away. It could be released today, and it would still be ahead of its time.
Replying to @mattyglesias
Also a guy with correct takes about AI consciousness.
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Ward Plunet retweeted
The master biographer reflects at 91. The Robert Caro interview. 0:00:00 – How Caro gets people to talk 0:05:03 – Does America need a little more Moses today? 0:12:42 – Moses the young idealist 0:17:57 – Watching Moses lose power 0:24:01 – Did Moses realize he was changing? 0:27:53 – Building during the Great Depression 0:32:51 – The threats and promises of Lyndon Johnson 0:36:08 – Could Kennedy have passed Johnson’s laws? 0:41:00 – Getting a book down to one sentence 0:46:21 – All the material that never made it into the books 0:52:59 – Loneliness
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Ward Plunet retweeted
A ‘hello world’ milestone for Project Suncatcher 🚀 After launching our prototype satellite a few weeks ago, we’ve now successfully sent a command up to orbit, booted up the TPU, ran the prompt, and received our first complete response back on earth - a haiku!
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No end to the innovation
1/4 Meet Qwenputer: Qwen3.5-4B with a full RISC-V CPU inside its weights, using the model's own Gated DeltaNet layers as RAM. It runs C and MicroPython in its forward passes, no external runtime. On DeepMind math: base 55–90%, base + Python tool 95–100%, Qwenputer 97.5–100%.
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One step and I am sure there will be many more.
Our first blind patient in a clinical trial with Stargardt disease received the PRIMA implant and at his first rehab session, he saw a letter, and during his second session, he read a word. Watch the video:
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Ward Plunet retweeted
Introducing Kimi K3.1 Pro: our most capable 3T-class open-weight model. 🔹 1M-token context, 2.8T total / 104B active params (MoE), Multimodal. 🔹 Full-project coding: games in Unreal, Unity & Godot. 🔹 Excels at parametric 3D modeling in Blender & CAD. 🔹 More reliable at finance work: Accurate modeling with hallucination down by 65%. 🔹 Matching the strongest proprietary models across coding, agentic and knowledge benchmarks. Kimi K3.1 Pro and K3.1 Pro Highspeed (2–3× faster) are now live on Kimi.ai, Kimi Work, Kimi Code, and the Kimi API. Open weights by Nov 4, 2026. 🔗 API: platform.kimi.ai 🔗 Tech blog: kimi.ai/blog/kimi-k3-1-pro
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This is great, and I would predict we see more of this going forward,.
Cancer patients with the same diagnosis often have very different tumor biology. Molecular testing can reveal underlying differences, but that's slow and expensive. Introducing Holon-S1, our platform to predict genes and biomarkers from routine pathology slides. • beats two other models at predicting spatial gene activity in a controlled comparison • has identified potentially novel biomarkers in breast cancer and colon cancer • evaluated across 16 organ types and more than 15 scanners, using slides from both formalin-fixed, paraffin-embedded and fresh-frozen tissue. We believe Holon-S1 has the potential to help researchers find new biomarkers in slides they already have, discover treatment targets, and bring more personalized cancer care within reach!
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Ward Plunet retweeted
"I designed my sequencing plan with AI agents, took it to Dana-Farber, and they validated it." That's @miriamgonp, an engineer in Spain with metastatic breast cancer who's building her own vaccine plan. I'm chasing the same thing in the US, and we're both in the same spot: standard treatments buy time, but delay is the game, not a cure. Neither of us wants to sit back and watch how that runs out. We could each do this quietly in private, but what's the fun in that? Doing it in the open means someone else might see it and realize they can do this too. It gets the industry paying attention, which is how this gets cheaper and faster for the next patient, and at the very least it makes the whole process far more transparent than it's ever been. The interesting part is that we're going about it differently. She drives the design herself with AI and has the experts check her work. I went the other way and handed the design to the experts at Serova. I have no idea which approach is better, and I love that we get to find out. I also love that you all get to watch us explore the cutting edge of curing cancer in real time! What a time to be alive! Which path would you take? Miriam's? Or mine?
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Ward Plunet retweeted
Why? How did we ever get so lucky find meaningful neurons inside neural networks? We finally have a theory: arxiv.org/abs/2610.20851 🧵🧵🧵
interpretability might be the most important scientific problem in the world right now, as I don't think we can solve alignment if we don't know what we're building. I think I have good news about it. I co-authored early work in mechanistic interpretability at OpenAI and came away pessimistic, because neural networks appeared to fold into arbitrary tangled knots. years later, I started openai's first large-scale automated interpretability project, finding about 2% of neurons legible with the primitive tools we had with modern agentic tools and a much closer look, the picture looks totally different. the vast majority in models up to trillions of parameters are legible, and their circuits beautiful. many famous examples of tangled neurons turned out to be misunderstood. The roadblocks I expected mostly aren't there. I now think ambitious interpretability will be solved by the time we need it most, and possibly quite soon, as automated scientists keep improving. it may be a bitter lesson for interpretability: the simple thing, at absurd scale, works already-clean.goodfire.com/
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Ward Plunet retweeted
Can AI agents do interpretability research? At @PrimeIntellect Residency program, we built BioCircuit, an RL environment where agents trace attribution graphs on Qwen3-4B, find the features behind a concept and get graded by intervening on prompts they've never seen. Link : amitprakash.in/biocircuit/
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Very interesting read and I look forward to what new level of understanding of the brain and NN this could lead to.
Working with AI models, I've arrived at what I consider the most significant pure-theory breakthrough of my research (in theoretical neuroscience) so far: arxiv.org/abs/2610.12426 Chaotic systems show what is colloquially called the butterfly effect, namely, a tiny nudge to the initial state grows exponentially in time. How fast the nudge grows depends on its direction. Each direction has its own growth rate, called a Lyapunov exponent, and the full set of rates is the Lyapunov spectrum. The Lyapunov spectrum is a rich (and diffeomorphism-invariant) characterization of chaos, telling us how many directions are chaotic, how many dimensions the attractor occupies, and how fast the dynamics generate information. In 1988, Sompolinsky, Crisanti, and Sommers (Physical Review Letters) introduced a nonlinear recurrent-network model of N randomly coupled neurons that becomes chaotic when the coupling strength exceeds a critical value. This network has since become a cornerstone of theoretical neuroscience, both as a model of the spontaneous activity of cortex and as the starting point for training recurrent networks on tasks. I have worked on this model for much of my research. In the same paper, the authors obtained the largest Lyapunov exponent from the ground-state energy of a Schrödinger equation and named the full Lyapunov spectrum as an open problem. In 2023, beautiful work by Engelken et al. (Physical Review Research) computed the full Lyapunov spectrum numerically. However, an analytical calculation of the full Lyapunov spectrum has remained out of reach. Four decades after the problem was posed, this paper derives the full Lyapunov spectrum at large N from a simple self-consistent single-site problem. This calculation has three steps. First, we lower every exponent by a constant s, which turns the question "how many exponents lie below s?" into the question "how many tangent directions decay?" We show that, if we drive the shifted tangent dynamics with a source and take the minimum-norm solution, the one-step response is the projector onto the decaying directions. Thus, the trace of this projector counts the decaying directions. This step is exact at finite N. Second, to work with the minimum-norm solution, we cast it as the vanishing-regularization limit of the solution of a least-squares problem. This regularized solution in turn solves a dynamical system with one field running forward in time and another running backward. Third, we apply the cavity method, that is, we add one neuron to the network, along with its forward and backward fields. The effect of the rest of the network on this neuron then reduces to the classical dynamical mean-field description of the activity of this neuron, plus two kernels that couple the forward and backward fields of this neuron to each other across time. Thus, the full Lyapunov spectrum follows from a single-site problem, which boils down to the self-consistent calculation of these kernels. The resulting theory agrees closely with simulations for the Lyapunov spectrum, the attractor dimension, and the entropy rate, and recovers known results, including the Schrödinger equation of Sompolinsky, Crisanti, and Sommers for the largest Lyapunov exponent. As a byproduct, the theory establishes analytically that the chaos is extensive, i.e., the attractor dimension and the entropy rate grow in proportion to N. I had assumed that this problem was analytically intractable. After working independently for 100 minutes with Max thinking, GPT-6 Astra produced the initial derivation, yielding a self-consistent problem whose solution matched simulations of large networks. I found this derivation intriguing, albeit complicated and somewhat mysterious (see AI Methodology in the paper). After investigating the structure of the proposed solution more deeply, together with AI models, I arrived at a physically transparent derivation. I am excited to apply this approach to other network models, trained networks, and, more broadly, to high-dimensional systems to which Lyapunov analysis is relevant, including AI models themselves. Of course, as with any paper, I took care to write up the paper clearly. A few broader thoughts... Neural circuits are high-dimensional nonlinear dynamical systems, and such systems are notoriously hard to understand. I would frame the central problem of theoretical neuroscience as understanding how such systems function, process information, learn, and generate behavior. Many people in the theoretical sciences are anxious about AI. However, in my field at least, we are nowhere close to fully understanding the high-dimensional computations unfolding in our brains. With AI, we could reach a level of understanding that so far we have only gestured toward. So, I am excited.
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Ward Plunet retweeted
Models can introspect to recover tokens deleted from their past CoT above chance. But how is this possible mechanistically? And why do some models use their introspection to make it less (not more) likely to answer the word they thought of when asked? 🧵
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More signs
I think I found a planet nobody knew existed. It's been hiding in NASA telescope data for seven years. At the end of this thread, you can fly to it yourself.
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Ward Plunet retweeted
Big, big, big, big props for quasiriemann and no Siegel zeroes (with many other beauties in there), I’m kicking myself for talking all over about it being within reach but not actually having pushed. There are some sad stories related to their users getting scooped / conflicts of interest (kakeya maximal comes to mind), and obviously we had some of the problems (without commenting on precise rumours). We should put that aside for today though. It’s obviously the most significant moment in mathematical history.
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